[aprssig] OpenTracker power supply

Gudday
I am finding more and more that people want trackers that have the ability
to keep on working for a while when the power dies.
I have been running mine on a recharageable 9 Volt cell and have had good
success as a standalone box.
What I would really like to do is to be able to provide a box that takes in
say 13.8 Volts, but also trickle charges the 9 Volt battery
just in case they need to take it prortable.
Comments on power supplies for trackers ?
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Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec at tech-software.net
web: http://www.tech-software.net
Brisbane AUSTRALIA